The invention relates to a conditional access system for controlling the access of receivers of end-users to a data content source in an uplink system, said uplink system comprising a scrambler for scrambling data content supplied from the data content source, an entitlement control message generator for generating entitlement control messages containing a control word and an entitlement identification and a transmitter for transmitting the scrambled data content and the entitlement control messages, in which a descrambler, and an entitlement control message decoder are associated to the receiver, and in which if a match between the entitlement in the entitlement control message and the entitlement of the end-user exists, the entitlement control message decoder supplies a control word to the descrambler for descrambling a part of the received scrambled content for which the receiver is entitled.
The invention further relates to an uplink system for use in such a conditional access system.
The invention further relates to a receiver for use in such a conditional access system.
Such a conditional access system is known from the article xe2x80x9cFunctional model of a conditional access system, published in EBU Technical Review, Winter 1995, No. 266, pages 64-77.
In present access systems a user pays access to an integral part of data content (e.g. a football match) and otherwise gets to receive nothing. The entitlement of the user is allocated to the integral part of the data content. Current conditional access systems provide for several types of entitlements to give access to services from a provider, which entitlements relate to the way of payment of the services.
The invention, however, has the object to draw the attention of the users more directly to the possibility of receiving an integral part of the data content, in order to stimulate the users to buy said data content part.
This object is achieved by the invention in that a separator is provided, coupled to the data content source for separating a part of the data content from said source into at least one object data stream representing a preselected object of the data content part and a remaining data stream representing the data content part without the object data, that the at least one object data stream is supplied to the input of the scrambler and that a combiner is connected to the output of the descrambler for combining the descrambled object data with the remaining data content, in which an individual entitlement is allocated to said object.
An integral part of the data content is analyzed to separate an essential object from the remainder of said integral part, e.g. the ball in the scene of a football match. In the broadcast signal to the user, this essential object is identified as being a separate object. This essential object is given a separate conditional access code, so that an individual entitlement is allocated to the object. For example the user is able to receive the remainder of the integral part of the data content for free, i.e. the remainder of the football match without the ball. By viewing the football match without a ball the viewer is stimulated to pay to see the complete scene.
It is observed, that in U.S. Pat. No. 5,442,701 the video signal is adapted in quality on analogue or digital level, in order to have a video signal with semi-quality. This adaptation is completely independent of the football scene. According to the invention, however, a scene adaptation is implemented by separating an essential object (such as a ball). Moreover, the invention has the advantage that the remainder of the integral part has a good quality and thus a more professional appearance, so that the user will be stimulated more to pay for a complete integral part of the data content (the complete football match).
The semi-quality version of the football match seems to be unusable. In the conditional access system according to the invention the remainder part of the data content is not unusable. For example, the conditional access system according to the invention could be generalized to programs consisting of more levels of conditional access (more tariff levels), in which the lowest (free of charge) could be worthwhile. It is referred for example to an electronic news paper having a basis level free of charge (see teletext), while you have to pay for in-depth information, photographs and so on.
The invention will be explained further by reference to the enclosed FIGURE showing the architecture of a preferred embodiment of a conditional access system according to the invention.
In general, in conditional access systems one could distinguish among others a service and an event.
A service is a sequence of programs under the control of a broadcaster which can be broadcasted as part of a schedule. The service is the central reference entity.
An event is a grouping of elementary broadcast data streams with a defined start and end time belonging to a common service, e.g. a football match, news flash, an entertainment show and so on. An event is always part of one and only one service, i.e. one event cannot be part of multiple services.
According to the invention a part of data content (event) from a data content source is separated into at least one object data stream representing a pre-selected object of the data content part and a remaining data stream representing the data content part without the object data. The at least one object data stream is scrambled and transmitted to several users. If a user has paid for the complete part of the data content, in particular for the object, the remaining data stream and the at least one object data stream are combined An individual entitlement is thus allocated to the object.